1. Field of the Invention
The present invention relates to the field of chain linking and, more particularly, to a sprocket chain master link used for coupling the ends of a handwheel chain common in the piping industry.
2. Description of the Related Art
The manufacturing and processing industries often use various diameter pipes and conduits to transport fluid materials from one location to another. Effective control and regulation of the transport of such fluids through the use of valves is of paramount importance in these industries. Although many pipe valve operations are automated, many various types of valves can be opened and closed manually by turning a handwheel attached to the valve. It is often the case, however, that these handwheels and associated valves may be difficult to access because they are located overhead or out of reach.
In order to allow operators to manipulate handwheels located overhead or out of reach, handwheels are designed with sprocket wheels having protruding teeth. A sprocket chain can be secured around the sprocket wheel with the individual sprocket links resting on the protruding teeth of the wheel. The actual length of the chain varies depending upon the distance of the wheel to the ground surface. By pulling on the chain, an operator can manually open or close the valve.
Installing or replacing sprocket chains can be a difficult task. It is necessary to clamp one end of the multiple links in a vise or with a type of locking pliers to hold the link securely while using another type of pliers to unwind the tail ends of the link which wrap back around themselves. After inserting the link from the other end of the chain into the disassembled link, the pried apart tail ends of the disassembled link must be placed back in their original position. It is not unusual to break the tail ends off when trying to open or close the individual links when being disassembled. When this occurs, the operator must try again to pull apart another link. An effective solution for the problems relating to installation and replacement of sprocket chain links for handwheels is a master link that can be quickly and effectively inserted or removed from the chain.
The prior art relating to sprocket chain master links or universal chain links does not appear to address the type of sprocket links used in the piping industry. U.S. Pat. No. 4,882,901 to James M. Lapeyre relates to a detachable link chain used as a conveyor or transmission chain. The Lapeyre patent describes a chain composed of a plurality of interconnected identical links which are attachable and detachable without need for pivot pins or other separate connecting hardware. These chain links, however, are quite distinct from the types of sprocket links used in the piping industry.
The existing prior art does not appear to address the problems associated with the difficulties in installing or replacing sprocket chain links used for handwheels. The present invention is specifically designed to facilitate the connecting and disconnecting of sprocket chains from handwheel sprockets. By using a master link that can be quickly detached and re-attached to an existing chain, such operation can save time and energy installing or replacing a sprocket chain.